[C++] ProxyBuilder logs discovery on level info and with proxy participantId
[C++] ProxyBuilder logs discovery on level info and with proxy participantId

Change-Id: I15cc1e39b84d471097c26cd6da5e53c1713d9abb

bmwcarit/joynr,bmwcarit/joynr,bmwcarit/joynr,bmwcarit/joynr,bmwcarit/joynr,bmwcarit/joynr,bmwcarit/joynr,bmwcarit/joynr,bmwcarit/joynr